I bought that 4.3" one from eBay but I'm a bit of a noob when it comes to this kind of thing so would someone be able to point out what needs removing and what needs soldering where from this picture? I can get a better/clearer picture if needed
[EDIT] Never mind, I recently bought a plug with several different interchangeable attachment things and one of them happened to be the right size for the screens power input, so I soldered an old USB to that attachment, plugged it in and it worked instantly from USB with no changes at all to the screen.
So I recommend the screen in my previous post for any noobs like me
Here it is being powered by my laptop (with my GameCube because my Pi isn't nearby)